I've checked in the cordova otp module it now supports Android and iOS, I've added a dependency on the barcode scanner plugin so that it is a complete package. There is one general generate method that will check if there is a secret stored if not it will fire up the barcode scanner to scan a secret and then store it. There are also separate methods that support these functions.
On the android side I use SharedPreferences and for iOS NSUserDefaults to store the secret. Currently the project is under my own name don't know how to move it.
As this is a security thing it would be great if others would take a look at because we want to be extra sure there is no obvious security hole in this.
Cheers, Erik Jan